PKSlike

PKSlike refers to proteins and gene products that resemble polyketide synthases (PKS) but do not conform to the canonical architecture of established PKS families. The term is used in genomics, enzymology, and natural product research to describe enzymes that carry PKS-like domains or share substantial sequence similarity with PKS domains while participating in non-traditional arrangements or pathways.

In terms of structure, PKSlike proteins may contain ketosynthase (KS) domains or KS-like motifs, and they frequently occur within larger multi-domain proteins or as unusual standalone modules. Their domain organization often diverges from the classic modular Type I or iterative PKS schemes, and some PKSlike proteins retain only fragments of the catalytic machinery or employ divergent active-site residues.

PKSlike sequences are found across bacteria, fungi, and plants, and they are commonly associated with secondary metabolite gene clusters or regulatory networks. They are thought to arise through domain shuffling and diversification of ancestral PKS-related modules, contributing to metabolic flexibility and novelty.

Functional roles for PKSlike proteins span potential involvement in polyketide-like biosynthesis, auxiliary steps in larger biosynthetic pathways, and non-catalytic functions such as scaffold formation or pathway regulation. As a research category, PKSlike helps broaden understanding of polyketide chemistry and enzyme evolution.

Researchers identify PKSlike candidates through genome sequencing, domain prediction, and phylogenetic analyses, followed by heterologous expression and biochemical assays to determine activity. The term remains descriptive, and its exact boundaries vary with ongoing discoveries in natural product biosynthesis. See also polyketide synthase, domain architecture, secondary metabolism, biosynthetic gene clusters.